This invention relates to twist closure caps for bottles and other containers and to a closure wherein a cap of a given size is made using less metal and gasket material, as well as using thinner metal plate. More particularly, the application relates to an improved cap shell shape, including a flared or tapered cap corner where the corner design provides a stiffer cap shell and a reduced cap blank size resulting in both metal and gasket material savings. Improved cap shell forming operations are also described in which the new cap corner shape is formed without distorting the finished cap shell.
A substantial number of glass and other containers are presently sealed with closure caps known as twist caps. These caps are characterized by a shaped metal cap shell with container engaging lugs formed on the lower edge of cap skirt. Additionally, each closure has a flowed-in plastisol gasket generally positioned between the cap corner and a stacking panel on the cap top. The most widely used caps of this type are further characterized by having a square or sharp crown corners so that generally flat covers are terminated in a right-angled depending straight skirt. By way of contrast, the cap of this invention has a shaped, or tapered, corner between the cap cover and the lower portion of the cap skirt. This corner shaping, as described more fully below, provides for the several advantages already noted, including the reduced use of metal and plastic materials.
Accordingly, an object of the present invention is to provide an improved closure cap.
Another object of the present invention is to provide a twist or screw cap utilizing lesser amounts of metal plate and gasket materials.
Another object of the present invention is to provide an improved method of manufacturing the improved closure cap.
Another object of the present invention is to provide an attractive and rigid twist cap manufactured of relatively light weight metal plate.
Other and further objects of the present invention will become apparent upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.